Bottom silo unloader

ABSTRACT

A bottom silo unloader for use in discharging moist grain from a sealed silo has a discharge tube set in the silo floor that leads from a casing in the center of the silo below floor level to the outside, and a discharge auger in the casing is driven by drive means adjacent the outer end of the tube. A pair of vertically aligned, right angle gear boxes are driven by the discharge auger and drive a sweep auger. A ring gear on which the upper gear box is mounted is rotated from the drive means to cause the sweep auger to rotate about the vertical axis of the silo and the gear boxes. A torsion arrangement suspends rotation of the ring gear when the sweep auger encounters heavy resistance to its movement around the silo.

BACKGROUND OF THE INVENTION

The oxygen-controlled storage of animal feeds in sealed silos requiresthat the silage be unloaded from the bottom of the silo. Generally,bottom silo unloaders have a sweep member which rotates about thevertical axis of the silo to move stored material to a center dischargeopening through which it drops into another conveyor means that iseither in or beneath the floor, that carries the material to theexterior of the silo. The material discharge opening from the dischargeconveyor means is provided with a sealed closure.

When a silo is used for the storage of relatively fine, granularmaterial such as shelled corn, the material handling problems are verydifferent from those which exist in the handling of materials such aschopped corn silage and haylage; and as a result the apparatus fordischarging grain requires different characteristics from what is neededin an apparatus to discharge chopped corn silage or haylage. Most of thecommercial grain unloaders now on the market for use with shelled corndepend upon gravity to unload the grain until it reaches its angle ofrepose, after which a sweep arm is made operative to remove theremaining grain. Because of this, there are limitations on the maximummoisture content and minimum particle size to insure free flow of thematerial. The moisture maximum is about 30 percent, and the shelled cornmust have been very carefully handled so as to have very few brokenkernels. If these requirements are not met, the material may becomenon-free-flowing, which makes it difficult to remove the material fromthe silo.

There is a definite need for a mechanically simple, rugged bottom silounloader which can be readily serviced and maintained by a farmer, andwhich is capable of handling shelled corn of high moisture content orshelled corn which has been cracked or split, whether such cracked orsplit corn is of a low or high moisture content.

SUMMARY OF THE INVENTION

In accordance with the present invention, a center discharge hole in thefloor of a sealed storage silo is provided with a casing that is set inthe floor, and a discharge tube extends from the interior of the casingto a point outside the silo wall. A discharge auger mounted in thedischarge tube is driven from a motor and reduction gear box that aremounted on the tube outside the silo wall, with the auger shaft beingcoupled directly to the output shaft of the gear box.

In the casing at the center of the silo floor are two verticallyaligned, right angle gear boxes. The lower gear box has a horizontalinput shaft directly coupled to the inner end of the discharge auger,and a vertical shaft on the axis of the silo connects the lower gear boxoutput with the upper gear box input. The upper gear box output shaft isdirectly coupled to the shaft of a sweep auger so the sweep auger isdriven by the motor through the discharge auger.

In order to rotate the sweep auger about the axis of the silo, there isa horizontally disposed ring gear that is rotatable in the casing, andthe upper gear box is mounted on the ring gear so as to rotate with it.Drive of the ring gear is taken off the output shaft of the reductiongear unit that drives the discharge auger, with the drive being througha ratchet and pawl arrangement and a long ratchet shaft that extendsfrom outside the silo into the casing where it has a worm in drivingengagement with the ring gear.

A satisfactory apparatus for discharging high moisture content shelledcorn from a sealed silo must be capable of responding to differences inthe density of the material through which it sweep auger passes. In thepresent arrangement, if the sweep auger encounters an area of highresistance in the material to be discharged, the heavy load on the longratchet shaft causes it to distort in torsion and put a reverse loadupon the ratchet. Under these conditions, when the pawl is disengagedfrom the ratchet for backward movement to pick up another ratchet tooth,the torsion loading of the ratchet shaft causes the ratchet to back upwith the pawl and thus suspends rotation of the ring gear. The suspendedring gear action continues until the sweep auger has removed enough ofthe packed material to reduce the resistance to movement of the sweepauger around the silo sufficiently that the ratchet and pawl is againeffective to rotate the ring gear.

In addition to the foregoing structural and operational features, thepresent apparatus includes novel means for deliverying material from theside of the casing away from the discharge auger into the dischargeauger for removal from the silo. When the sweep auger is in that portionof the silo which is most remote from the discharge auger, it feedsmaterial into the side of the casing which is away from the dischargeauger, and this material is moved into the discharge auger by a pair ofradially extending paddles on the vertical shaft that connects the upperand lower gear boxes.

THE DRAWINGS

FIG. 1 is a generally schematic view through the foundation and thelower end portion of a silo provided with the material dischargeapparatus of the invention;

FIG. 2 is a fragmentary, broken sectional view on an enlarged scaletaken substantially as indicated along the line 2--2 of FIG. 1 with thesilo wall and floor omitted for clarity of illustration;

FIG. 3 is a fragmentary side elevational view on an enlarged scale withparts broken away, taken substantially as indicated along the line 3--3of FIG. 2;

FIG. 4 is a fragmentary end elevational view taken substantially asindicated along the line 4--4 of FIG. 3;

FIG. 5 is a fragmentary sectional view taken substantially as indicatedalong the line 5--5 of FIG. 3;

FIG. 6 is a sectional view taken substantially as indicated along theline 6--6 of FIG. 3;

FIG. 7 is a fragmentary transverse sectional view taken substantially asindicated along the line 7--7 of FIG. 2;

FIG. 8 is a fragmentary sectional view taken substantially as indicatedalong the line 8--8 of FIG. 7; and

FIG. 9 is a fragmentary sectional view on an enlarged scale takensubstantially as indicated along the line 9--9 of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings in detail, and referring first to FIG. 1, asilo, indicated generally at S has a concrete foundation F with ahorizontal top surface providing a floor f; and a continuous silo wall Wsurrounds the foundation and extends upwardly. The upper end (not shown)of the silo is closed by a sealed roof and is provided with any suitablebreather structure for preventing air from coming into contact withmaterial stored in the silo while at the same time permitting expansionand contraction of air in the top of the silo as the ambient temperaturechanges.

At the center of the silo floor is a discharge opening 10 in which acasing 11 is positioned in the foundation, and from a hole in one sideof the casing 11 a discharge tube 12 which is embedded in the foundationF extends outside the silo where it is provided with a discharge opening13. A discharge auger 14, mounted in the discharge tube 12, includes anauger shaft 15 and a helix 16.

Mounted on the projecting outer end portion of the discharge tube 12 isa motor mounting platform 17 on which an electric motor 18 is supported,and suspended from the platform 17 is a reduction gear unit 19 which isdriven from the motor 18 by a drive belt 20 that is trained around amotor sheave 21 and an input sheave 22 on the input shaft of thereduction gear unit 19. An output shaft 23 of the unit 19 is directlycoupled to the discharge auger shaft 15.

In the casing 11 is a lower right angle gear box 24 that has an inputshaft 25 directly coupled to the discharge auger shaft 14; and avertical shaft 26 which is on the vertical axis of the silo connects thelower right angle gear box 24 with an upper right angle gear box 27which is carried on a horizontal ring gear 28 that is mounted in the topof the casing 11 for rotation about the axis of the vertical shaft 26.The upper right angle gear box 27 has an output shaft 29 which isdirectly coupled to a sweep auger shaft 30 of a sweep auger 31 that hasa helix 32 resting upon the floor f of the silo. The ring gear 28 isrotated by a ring finger gear drive means, indicated generally at 33(FIGS. 2 to 5) which includes an intermittent motion device, indicatedgenerally at 34 in FIG. 5. The ring gear drive will be described in moredetail hereafter. Rotation of the ring gear on which the upper rightangle gear box 27 is mounted rotates the sweep auger 31 around the siloas the unloader operates so as to progressively bring the sweep augerhelix 32 into contact with different parts of the material in the bottomof the silo and feed the material into the casing 11 for removal by thedischarge auger 14.

The details of the mounting for the motor 18 and reduction gear unit 19are seen in more detail in FIGS. 3 and 4, and in particular those viewsshow that a mounting 35 for the reduction gear unit 19 includes a rod 36that is pivoted at 37 beneath one side of the motor platform 17, and therod 36 is threaded at its outer end to adjustably receive a yoke 38which carries the reduction gear unit 19 so as to maintain tension inthe drive belt 20. Adjustment of the yoke 38 along the threaded rod 36maintains the gear unit output shaft 23 in alignment with the dischargeauger shaft 15 to which it is coupled.

FIGS. 2 and 7 to 9 show more details of the casing 11 and of themounting of various components in and on it. Thus, it is seen that thecasing 11 is square, and in each of its corners is a flange 39 on whichthe periphery of the ring gear 28 is supported. Each of the flangemembers 39 is provided with an upright stud 40 on which a ring gearconfining member 41 is journalled; and a ring gear retaining plate 42 iscarried on the studs 40 and bolted to the flanges 39 by bolts 43 whichextend through the studs 40 that also serve as spacers for the retainingplate 42 that hold it slightly above the ring gear 28. On opposite sidesof the ring gear are angle brackets 44 which carry the upper right anglegear box 27; and as best seen in FIG. 8 the lower right angle gear boxin fact is suspended from the upper gear box 27 on the shaft 26 and isconfined against lateral movement by angle members 45 that are securedto the bottom of the casing 11; but the lower right angle box 24 is freeto float vertically with respect to the angle members to retain properalignment with the discharge auger shaft 15.

Mounted on the vertical shaft 26 that connects the upper and lower gearboxes are generally radially extending arms 46 which function to movematerial deposited in the right hand side of the casing 11 as seen inFIG. 7 into the discharge auger 14. In addition, the sweep auger 31 isprovided with one or more elongated pins 47 that assist in breaking upany material that might tend to clog the feed from the inner end of thesweep auger into the casing.

Referring now particularly to FIGS. 2 to 5 and 8, the drive means 33 forthe ring gear 28 includes an output sprocket 48 on the output shaft 23of the reduction gear unit 19, and a counter shaft 49 which isjournalled in the brackets that support the motor platform 17. Asprocket 50 on the counter shaft is driven by a chain 51 from thesprocket 48 so as to drive the counter shaft 49 at a substantially lowerspeed than the discharge auger 14.

As best seen in FIGS. 2, 3 and 5, a laterally extending bracket 52 whichis beneath the motor platform 17 contains a journal 53 for a longratchet shaft 54 that is carried in a tube 55 in the foundation of thesilo and extends into the casing 11 (see FIG. 8) where it has a worm 56that is in driving engagement with equally spaced depending studs 28a ofthe ring gear 28. Thus, rotation of the ratchet shaft 54 causes the ringgear 28 to rotate and thus rotate the sweep auger 31 around the centerof the silo.

Rotation of the ratchet shaft 54 is provided by a ratchet and pawlstructure which forms the intermittent drive means 34. As best seen inFIGS. 3 and 5, the ratchet and pawl structure includes an eccentric 57on the counter shaft 49 and a bearing 58 surrounding the eccentric. Apair of arms 59 which are integral with the bearing 58 form a crank arm,and a pivot pin 60 between the arms 59 receives a bifurcated link 61which is journalled on the projecting outer end portion 54a of theratchet shaft 54. A ratchet 62 is keyed to the shaft portion 54a betweenthe halves of the bifurcated link 61, and a pawl 63 is pivoted on thepivot 60 so as to engage the teeth of the ratchet 62 as illustrated inFIG. 5.

In operation, the eccentric movement of the member 57, transmittedthrough the crank arm 59, causes the pawl 63 to oscillate transverselyas seen in FIG. 5 and successively pick up the teeth of the ratchet 62to impart intermittent rotation (counter-clockwise as seen in FIG. 5) tothe ratchet shaft 54. This, in turn, imparts intermittent rotarymovement to the ring gear 28 to move the sweep auger 31 slowly about thefloor f of the silo.

When the sweep auger 31 encounters an area in which the material in thesilo is particularly densely packed, the resulting heavy resistance tomovement of the sweep arm about the silo floor produces a torsionalloading of the ratchet shaft 54 which is in a clockwise direction asseen in FIG. 5. Under these circumstances, the left to right movement ofthe pawl 63 which ordinarily would pick up the next adjacent ratchettooth is ineffective, because the torsional loading of the shaft 54causes the ratchet 62 to rotate clockwise as seen in FIG. 5 so that thepawl 63 remains engaged with the same tooth of the ratchet 62 andaccordingly produces no rotation of the ring gear 28. This permits thesweep auger 31 to continue to feed material until it has eliminated thedense packing and the ratchet and pawl drive can again produceintermittent rotation of the ring gear 28.

As seen in FIG. 3, the discharge auger opening 13 is provided with aclosure 64 that is hinged at 65; and a pivoted bolt 66 receives a wingnut 67 so that the closure 64 may be selectively sealed against thelower end of the discharge opening 13 or released for movement about thehinge 65 to a fully open position.

The helix 16 of the discharge auger 14 is seen in FIG. 3 to terminateadjacent the inner side of the opening 13 so as to prevent it frompacking material against the closed outer end of the discharge tube 12;and in order to assure flow of material from the tube 12 into thedischarge opening 13, one or more radial pins 68 project from the augershaft 14 generally above the center line of the discharge opening 13.

The foregoing detailed description is given for clearness ofunderstanding only and no unnecessary limitations should be understoodtherefrom, as modifications will be obvious to those skilled in the art.

We claim:
 1. In a bottom silo unloader for use in the discharge of moistgrain from a sealed cylindrical silo that has a floor with a centerdischarge hole, in combination:a casing in said discharge hole that hasan upper edge substantially flush with the floor; a discharge tubecommunicating with said casing beneath the floor, said discharge tubehaving a discharge opening outside the line of the silo wall and anairtight closure for said opening; a discharge auger in said dischargetube; drive means mounted outside the silo and drivingly connected tosaid discharge auger; a lower right angle gear box in the casing whichhas a horizontal input shaft coupled to the discharge auger; means atthe bottom of the casing restricting movement of said lower gear box; anupper right angle gear box having a horizontal output shaft; a verticalshaft drivingly connecting said gear boxes; a sweep auger above the silofloor and rigidly drivingly connected to the output shaft of the uppergear box for revolving the sweep auger on its axis to feed grain intothe casing; a ring gear supported in the upper part of the casing forrotation about the axis of the vertical shaft; means mounting said uppergear box on said ring gear; and means for driving the ring gear from thedrive means to rotate the sweep auger about the center of the silo. 2.The combination of claim 1 in which the means for driving the ring gearincludes means responsive to high resistance to rotation of the sweepauger around the silo for suspending rotation of the ring gear until thehigh resistance is relieved by axial revolving of the sweep auger. 3.The combination of claim 2 in which the means for driving the ring gearincludes a ratchet and eccentric pawl drive outside the silo, a ratchetshaft extending from the ratchet into the casing beneath the silo floor,and means on the ratchet shaft in driving engagement with the ring gear,torsional distortion of said ratchet shaft under heavy load causing thesuspension of ring gear rotation by causing the ratchet to rotatereversely as the pawl withdraws from engagement with the ratchet.
 4. Thecombination of claim 1 which includes generally radially extending meanson the vertical shaft for moving grain into the discharge auger from theportion of the casing remote from said auger.
 5. The combination ofclaim 1 in which the discharge opening is in the bottom of the dischargetube beneath the outer end portion of the discharge auger, and in whichthere is a generally radially extending feed pin on the discharge augershaft above said discharge opening.
 6. The combination of claim 1 inwhich the drive means includes a motor and reduction gear box which hasan input shaft driven from the motor, said gear box having an outputshaft directly coupled to the discharge auger.
 7. The combination ofclaim 6 in which the means for driving the ring gear includes an outputmember on the gear box output shaft, and means including an intermittentmotion device driven from said output member.
 8. The combination ofclaim 7 in which the intermittent motion device includes a counter shaftdriven by the output member, an eccentric on said counter shaft, a pawlreciprocated by said eccentric, a ratchet which has teeth engaged by thepawl, a ratchet shaft extending from the ratchet beneath the silo floorinto the casing, and means on the ratchet shaft in driving engagementwith the ring gear.
 9. The combination of claim 8 in which the ratchetshaft can flex torsionally when the sweep auger encounters highresistance to rotation around the silo, said torsional flexing causingthe ratchet to rotate reversely as the pawl withdraws from engagementwith it, whereby rotation of the ring gear is suspended until said highresistance is relieved by axial revolving of the sweep auger.
 10. Thecombination of claim 1 in which the casing has flange means near itsupper edge on which the ring gear rests, a plurality of gear confiningmembers surmounting said flange means substantially in contact with thering gear, and a ring gear retaining plate supported on the flange meansslightly above the ring gear.
 11. The combination of claim 10 in whichthe casing is rectangular, the flange means comprises a flange member ineach corner, there is a rotatable gear confining member on each flangemember, and the ring gear retaining plate rests on spacers about whichthe gear confining members rotate.
 12. The combination of claim 1 inwhich the ring gear has a circumferential array of equally spaceddepending studs, and the means for driving the ring gear includes ahorizontal driven shaft and a worm gear on said shaft which engages saidstuds to rotate the ring gear. .Iadd.
 13. In a bottom silo unloader, thecombination of a casing which sets in a discharge hole provided in thefloor of a silo, a discharge tube which communicates with said casingadjacent the base thereof and has a discharge opening for locationoutside the line of the silo wall, a discharge auger in said dischargetube, drive means drivingly connected to said discharge auger; a lowergear box in the casing which has an input shaft coupled to the dischargeauger; an upper gear box having an output shaft; a vertical shaftdrivingly connecting said gear boxes such that the output shaft of theupper gear box turns on its axis with rotation of the input shaft of thelower gear box; a sweep auger to move over the silo floor which isdrivingly connected to the output shaft of the upper gear box forrevolving the sweep auger on its axis to feed material into the casing;a ring gear supported in the casing for rotation about the axis of thevertical shaft; the upper gear box being mounted on said ring gear toturn therewith; and means for driving the ring gear from the drive meansto rotate the sweep auger over the floor of the silo about the axis ofthe vertical shaft. .Iaddend..Iadd.
 14. The combination of claim 13 inwhich the means for driving the ring gear includes means responsive tohigh resistance to rotation of the sweep auger for suspending rotationof the ring gear until the high resistance is relieved by axialrevolving of the sweep auger. .Iaddend.